Is it normal to have no desire for sex?

I'm 19 years old and have no sexual desires whatsoever. I'm very busy with my education as work as an intern, and I find I have no time in my life to think about it even if I wanted to. I find happiness by going out with my friends, visiting different places, and spending time with my family. I've been dating but never have I really thought about "doing it." Is this unnatural, or is it just the way I am?